Ladders



Sept. 2, 1969 v. J. PoPoLl- 3,464,521

LADDERS Filed Nov. 8, 1967 2 Sheets-Shea?l l v. J. PoPoLl 3,464,521

LADDERS 2 Sheets-Sheet 2 Filed Nov. 8, 1967 Sept. 2, 1969 United States Patent Office 3,464,521 LADDERS Vincent J. Popoli, 1021 Washington St., South Braintree, Mass. 02184 Filed Nov. 8, 1967, Ser. No. 681,331 Int. Cl. E06c 1/00, 7/08 U.S. Cl. 182-207 6 Claims ABSTRACT F THE DISCLOSURE Extension ladders of aluminum and magnesium are widely used because their weight is substantially less than that of a wooden ladder of the same length and their life is not aiTected by moisture. At the same time, their side rails are much more ilexible and in extension ladders this becomes very objectionable and is attended by equally objectionable side sway.

The general objective of the invention is to eliminate this objectionable side rail flexibility without altering the ladder construction or affecting its weight to an objectionable extent, an objective attained by securing long strips to the outer faces of the ladder that are provided by the bottom walls of the channels which the extruded rails establish.

In the accompanying drawings, there is shown an illustrative embodiment of the invention from which these and other of its objectives, novel features, and advantages will be apparent.

In the drawings:

FIGURE 1 is a fragmentary face view of an extension ladder in accordance with the invention,

FIGURE 2 is a like side view thereof,

FIGURE 3 is a section on a substantially increased scale and taken approximately along the indicated lines 3 3 of FIGURE 2, and

FIGURE 4 is a section, also on a substantially increased scale, taken approximately alng the indicated lines 4 4 of FIGURE 1.

The extension ladder, generally indicated at may be made of aluminum, magnesium, or plastic and consists of sections 11 and 12 having, respectively, pairs ot side rails 13 and 14 with the side rails 13 interconnected by rungs 15 and the side rails 14 interconnected by rungs 16 The side rails of such ladders are conventionally extrusions, sometimes U-shaped but more commonly I- shaped with each rail thus establishing inwardly disposed and outwardly disposed channels, the channels being relatively shallow. The inner channels are designated by the suix addition A to the reference numeral for the rails and the outer rail channels are similarly distinguished by the sufix addition B. The section 11 is somewhat wider than the section 12 and is the lower section and includes means slidably connecting the rails of the section 12 thereto, such means being conventionally a partition 17 in each of the inner channels 13A of the rails 13 and dening with one of the walls of that channel a relatively Patented Sept. 2, 1969 narrow slot 18 slidably receiving one of the walls of the channel 14B of the proximate rail of the section 12.

In practice the at bottom of each rail establishes a side of the ladder and the rungs extend therethrough and are upset against the outer faces of the channel bottoms to lock the side rails against rung shoulders 15A and 16A, respectively, such upset protruding ends being indicated at 19 in FIGURES 3 and 4.

The ladder, as thus far detailed, is conventional with means for extending it and locking it in extended positions being omitted to simplify the drawings. Such ladders are widely used but have the objectionable features that the rails bow too easily and that there is considerable side sway when extended to any substantial extent.

In accordance with the invention strips 20 are secured to the rails 13 and strips 21 to the rails 14. In practice, the strips are wood, preferably of a width such that they may t within the outwardly opening channels, of a length coextensive with the channel length, and of a thickness such that they do not protrude to any substantial extent from the channels when secured therein. In practice, stock in the order of tive-eighths inch in thickness is satisfactory and while cost and weight of the strips is important, it is essential that the strips be thin enough to be relatively flexible.

The strips are shown as anchored to the sides of the ladder sections by a plurality of bolts 22, one bolt being between each rung. As indicated in FIGURES 3 and 4, the strips are drawn against said sides by the nuts 23 and become slightly bowed over the protruding ends of the rungs thus to render the strips effective to eliminate objectionable side sway with the width of the strip being such as to suitably stiifen the sections.

It will thus be apparent that the invention enables ladders, such as aluminum and magnesium ladders, to be made safer to use without materially affecting their weight or cost.

I claim:

1. A ladder comprising side rails, each providing a channel, the channel bottoms being the side walls of the ladder and of a width substantially greater than the channel depth, a plurality of rungs, the ends of the rungs protruding a short distance through said channel bottoms and locked thereto to interconnect said rails, a wood strip for each rail of a Width greater than its thickness and extending substantially the length of that rail, and a plurality of connecting means locking each strip against the outer surface of the side wall provided by the appropriate channel in a side-to-side relationship with the connecting means located between said rung ends thereby to brace said ladder against side sway, the width of each strip stiffening the ladder against bending, the portions of the strip between the connecting means being bowed over the rung ends.

2. An extension ladder comprising irst and second sections, each section including side rails, 'each providing a channel, the channel bottoms being the side walls of the ladder and of a width substantially greater than the channel depth, a plurality of rungs, the ends of the rungs protruding a short distance through said channel bottoms and locked thereto to interconect said rails, one section being wider than the other and with corresponding side walls of the channels of one section slidable within the channels of the other sections, a wood strip for each rail of a width greater than its thickness and extending substantially the length of that rail, and a plurality of connecting means locking each strip against the outer surface of the side wall provided by the appropriate channel in a side-to-side relationship with the connecting means located between the rungs and with the portions of the strip between the attaching means being bowed over said rung ends thereby to brace said ladder against side sway, the width of each strip stifening the ladder against bendmg.

3. The extension ladder of claim 2 in which the strips are wood.

4. The extension ladder of claim 2 in which the channels open toward each other.

5. The extension ladder of claim 2 in which each rail 6. The extension ladder of claim 4 in which each rail is approximately of the length, width and depth of the outwardly opening channel in which it is located.

References Cited UNITED STATES PATENTS 983,213 1/1911 Dahiuet a1. 1s2-219 2,144,293 1/1939 Hu11 1x2-219 2,594,070 4/1952 Reagle 182,-219

10 3,232,378 2/1966 Larson 1232-228 REINALDO P. MACHADO, Primary Examiner US. C1. X.R.

is approximately I-shaped in cross Section providing in- 15 182-219 wardly and outwardly opening channels housed within. 

